Cutting fluid and coolant



Patented Jan. 13, 1953 CUTTING FLUID AND COOLANT Ernst Laug, Union City,N. J assignor to Socony- Vacuum Oil Company, Incorporated, a corporationof New York No Drawing.

Application March 20, .1950,

Serial No. 150,823

This invention relates to an aqueous composition of matter adapted,particularly in diluted form, for use as a coolant and lubricating agentin metal cutting and similar operations.

In the machining of metals in operations such as cutting, threading,tapping, and the like it is customary to flood the tool and work with acoolant to carry away heat from the tool and work, and normally suchcoolants are also so compounded as to lubricate the operation. Due tothe high unit pressures involved, particularly in high speed operations,the fluid, if used also as a lubricant, must be an exceptionally capablelubricant. Many such fluids are emulsified petroleum oil base fluids,although in some cases it would appear that non-petroleum base fluidsare more acceptable. The present invention is found in the latter field,i. e., the non-petroleum base lubricants.

It is an object of this invention to provide a novel cutting and coolantfluid of the class described in the form of an aqueous emulsion, capableof being used either as formed or in dilute form, preferably in diluteform, which will be effective as a coolant and lubricant under theconditions noted.

Another object is the provision of such a fluid incorporating optimumproportions of emulsifying soaps and lubricating agents. Still anotherobject is to provide a stable, non-corrosive, rustinhibiting water-basemetal processing lubricant. Still other objects will'appear hereinafter.

The above and other objects are accomplished by the provision ofan-aqueous emulsion of mixed soaps of castor oil fatty acids, withcertain glycols, phosphates, and inhibitive agents.

The compositions of matter with which this invention is concerned arespecifically emulsions containing, in combination, potassium soaps ofcastor oil fatty acids, triethanolamine soaps of castor oil fatty acids,triethanol amine phosphates, water soluble polyalkylene glycols, andinhibitive substances.

Typical formulations of the composition will fall within the followingranges:

(8) Water Balance to 100% Norr..TEAis an abbreviation fortriethanolamine.

" '3 Claims. (01.252-343) The above formulation is unique in that, inaddition to the characteristics furnished by the individual components,various combinations of the components either amplify individualcharacteristics or impart entirely new properties to the product. Asillustrations, the following may be cited. It is understood, of course,that these observations apply only to the combinations which exist inthis particular formulation.

1. The combination of potassium castor oil soap, triethanolamine castoroil fatty acid soap, water soluble polyalkylene glycol andtriethanolamine phosphate-results in a product, water solutions ofwhich, on drying, leave a soft, residual film.

2. The combination of water soluble polyalkylene glycols andtriethanolamine phosphates imparts greater film strength characteristicsto the product than the use of either one alone. This same combinationacts also as an efiicient foam depressor.

3. The combination .of triethanolamine phosphate and sodium nitrite is abetter inhibitor against corrosion of ferrous metals than eithermaterial alone.

4. The water-soluble polyalkylene glycols, besides imparting filmstrength to the product, are also good lubricity agents.

5. Sodium mercaptobenzothiazole prevents corrosive action on copper,brass, bronze and allied metals by the soaps present in the composition.Furthermore, thismaterial possesses some germicidal properties.

A composition within the above defined field may be made by compoundingtogether the following ingredients:

TABLE II I Weight percent Castor oil 13.50 Castor oil fatty acids 1.75Potassium hydroxide 2.75 'I'riethanolamine 11.50 phosphoric acid 2.25

Nora-The polyalkylene glycol constituent used above is one suppliedunder the Carbide and Carbon Chemical Corp. trade name of Ucon 50 HB5100 and is a commercial polyalkylene glycol product having a Sayboltviscosity of 5000- 5200 at F. and 013165- at 210 R, an average specificgravity of about 1.063, apour 3 test of about 20 F. and a flash of about450 F. Generally similar products will be similarly useful.

This material may be compounded by charging the castor oil to anagitated, steam-jacketed kettle, and heating to about 110 to- 120 F.Then the potassium hydroxide (a 50% water solution) may be added slowlywith stirring. The temperature of the soap thus formed is graduallyraised to about 180 F. and agitation is continued for about one andone-half hours, until saponification is completed. With continuingagitation, the triethanolamine is added, followed by the polyalkyleneglycols and the phosphoric acid. After about half an hour furtherstirring, the batch is allowed to cool to about 120 F. Water is addedslowly to prevent excessive foaming and stirring is continued, withslight heating, if necessary until the solution is clear. Then thesodium nitrite is added, and when it is dissolved, the sodiummercaptobenzothiazole and phenol are added. After stirring untilthoroughly homogenized, the batch may be drawn.

The above procedure yields a lubricant base coolant composition havingthe following characteristics TABLE III Color Light brown (clear) OdorSlightly germicidal Specific gravity 60 F--- 1.078 Stability uponfreezing' Satisfactory Reaction Neutral pH 1-15 distilled water 8.25

This composition of matter is preferably used as a coolant and lubricantfor metal working in diluted form, the following having been found to beadvisable proportions:

TABLE IV Operation Dilution Tapping l-lO to l-l5 Drilling." 1l5 to l-25Grindingslunc l-50 to l-60 When so used, the material is found to be aquite eflicient coolant andlubricant, as shown b'y the following:

Tapping test Standard. Socony-Vacuum Solvac 4l0-1-15 tap water 100%..Test. Composition of Table 11-1-15 tap water Almen pin test In the Almenpin test, a standardized test current in the trade, the composition ofTable II, diluted 1-15 with tap water, was found to bear an OK load'of30,000 pounds per square inch.

Drilling test In this test, a commercial high speed: drill", diameter,is run to failure, drilling through 4 a thick plate of SAE 3140 steel.The composition of Table II, diluted 1-15 with tap water, was found toyield 156 holes to drill failure.

Corrosion E? Reagivc um: 1 y 70 F., 12 hours l-l5 tap water Nil.

l-30 tap water Nil.

1-45 tap water Nil.

1-60 tap water Nil.

ll00- tap water Iraco The composition is stable when diluted with hardwater, since when diluted 1-15 with a water of 200 p. p. m. or lesshardness, not more than a slight cloud will be formed.

In compounding materials of the kind disclosed herein, certain items ofimportance should be noted.

First, the total amount of soaps may vary from about 18 per cent toabout 24 per cent, and the proportion of triethanolamine soap should begreat enoughto plasticize the potassium soap without giving rise toexcessive foaming. This will be accomplished by from about 2 per cent toabout 5 per cent ofthe total.

The action of the triethanolamine phosphate upon solubility of theglycols limits the amount of thismgredientto not over about 13 per cent.

The polyalkylene glycols appear to be most effective at-about 4 percent.

The sodium nitrite corrosion inhibitor and phenol germicide may bereplaced by other materials of similar capabilitv.

The inherent capability of these compositions resides in the combinationof soaps, phosphate, and glycols particularly, and the broadest form ofthe invention therefor may be said to be embraced in compositions madeby compounding together.

TABLE-V I V 7 Weight percent Potassium soaps of castor oil fatty Iclaim:

1. An aqueous emulsion-form coolant and lubricant composition of matterproduced by compounding together Weight percent Potassium soaps ofcastor oil fatty acids 17 to 20 Triethanolamine soaps of castor oilfatty acids 2 to 5 Triethanolamine phosphat 3 to 13 Water solublepolya'lkylene glyco1s' 3 to 5 Rust inhibitive salts of sodium 2.25 to 4Phenol germicide 1 to 1.5 Water To balance 2 An aqueous emulsion-formcoolant and lubricant composition of matter produced by compoundingtogether Weight percent Potassium soaps of castor oil fatty acids 17 to20 Triethanolamine soaps of castor oil fatty acids 2 to 5Triethanoiamine phosphate 8 to 13 Water soluble polyalkylene g1yco1s 3to 5 Sodium mercaptobenzothiazole (solution--45-50%) 0.75 to 1.5 Sodiumnitrite 1.5 to 2.5 Phenol 1 to 1.5 Water To balance 3. An aqueous andemulsion-form coolant and lubricant composition of matter produced bysaponifying the castor oil and castor oil fatty acids with potassiumhydroxide, adding triethanolamine to the reaction mixture, then addingglycols, phosphoric acid, sodium nitrite, phenol, sodiummercaptobenzothiazole solution, and the required amount of water, thuscompounding together REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,238,478 Ott Apr. 15, 19412,252,385 Orozco Aug. 12, 1941 2,291,066 Waugh July 28, 1942 2,318,629Prutton May 11, 1943 2,470,913

Bjorksten May 29, 1949

1. AN AQUEOUS EMULSION-FORM COOLANT AND LUBRICANT COMPOSITION OF MATTERPRODUCED BY COMPOUNDING TOGETHER